Sewing machine conversion assembly

ABSTRACT

Apparatus for converting an ordinary sewing machine into a machine that will cut fabric. The apparatus comprises a cutter that is inserted into the sewing machine needle holder, a presser foot, a throat plate containing a recess adapted to permit the cutter to pass through and retaining means surrounding the recess. Two types of cutters each with a different blade design can be inserted into the needle holder, one cutter is capable of making a continuous straight cut and the other cutter is capable of making a continuous pinking cut.

United States Patent 91 Sztari [4 Oct. 16, 1973 SEWING MACHINECONVERSION ASSEMBLY [22] Filed: Nov. 23, 1970 [21] Appl. No.: 91,980

[52] U.S. Cl. 112/122 [51] Int. Cl D05b 37/00 [58] Field of Search112/122, 128, 129, 112/130, 81, 82, 260, 123, 127; 206/66, 1 R, 16 R, 17

[56] References Cited UNITED STATES PATENTS 139,350 5/1873 Allen 112/1281,891,308 12/1932 Gruman... 112/122 7 2,948,244 8/1960 Enos 112/2602,048,268 7/1936 Kucera 112/128 1,264,886 5/1918 Bergwardt 112/123 X691,203 1/1902 Sullivan ..112/128 X 3 ,459,293 8/1969 Vitale., .206/163,072,244 1/1963 Smith ..206/l7 1,980,705 ll/l934 Sigoda ..1 12/81 2,11/1939 Routtenberg.... 112/122 1,341,450 5/1920 Zawistowski 112/ 122 X907,617 12/1908 Merrowm. 112/129 453,429 6/1891 Murphy. 112/128 323,4398/1885 Ober 1 12/129 2,817,434 12/1957 Schmetz et al ..206/66 X PrimaryExaminer-H. Hampton Hunter Attorney-Donald J. Fitzpatrick [57] ABSTRACTApparatus for converting an ordinary sewing machine into a machine thatwill cut fabric. The apparatus comprises a cutter that is inserted intothe sewing machine needle holder, a presser foot, a throat platecontaining a recess adapted to permit the cutter to pass through andretaining means surrounding the recess.

Two types of cutters each with a different blade design can be insertedinto the needle holder, one cutter is capable of making a continuousstraight out and the other cutter is capable of making a continuouspinking cut.

5 Claims, 13 Drawing Figures Pmammum 16 ms 9 k M k w k v Q BY DMM J. EJQMM' ATTORNEY SEWING MACHINE CONVERSION ASSEMBLY BACKGROUND OF THEINVENTION 1. Field of the Invention This invention relates to aconversion kit adaptable for installation as a unit on a sewing machine.By utilizing the actuating mechanism of the needle arm the conversionkit rapidly transforms the sewing machine into a machine capable ofcutting fabric.

2. Description of the Prior Art It is well known in the art that sewingfabric requires an assortment of cutting instruments. For example incutting fabric when a pattern is used a pair of scissors and pinkingshears are normally employedby the seamstress or dressmaker.

After the pattern is used to outline a design on the fabric, the designmust be cut out. This is accomplished by hand cutting with a pair ofscissors. Depending upon the type of fabric selected by the dressmakerthis can be a slow and tedious operation. If the dressmaker is using aheavy fabric such as corduroy, tweed or an upholstery fabric, thecutting operation canalso be quite difficult and laborious. 7

Aside from the physical effort expended in hand cutting fabric thecutting instruments must be adequately maintained. If one attempted tocut out a pattern with dull and poorly maintained equipment this tedioustask would be unnecessarily burdened.

SUMMARY OF THE INVENTION It is an object of this invention to provide aconversion kit that can be readily installed as a unit in a sewingmachine thereby transforming the sewing machine into a machine capableof cutting fabric.

A further object of this invention is to provide a flat blade cutterthat can be inserted into a sewing machine needle holder to produce astraight cut.

Still a further object of this invention is to provide a cutter with anangular blade that can be inserted into the sewing machine needle holderto produce a pinking cut.

The objects of this invention are achieved by inserting a speciallydesigned cutter into a sewing machine needle holder in place of a sewingneedle, by attaching a presser foot having a cutter accommodatingaperture to a presser bar and by placing a throat plate having a recesscut therein to permit passage of the cutter bar into the sewing machinebase throat plate aperture.

These and other objects will be apparent from the disclosure and claimswhich follow.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a cutterinserted into a sewing machine needle holder and a presser foot attachedto a presser foot bar.

FIG. 2 is a side view of a cutter used to produce a straight cut.

FIG. 3 is a front view of a cutter used to produce a straight cut andshowing a beveled edge.

FIG. 4 is a top view of a cutter used to produce a straight cut.

FIG. '5 is a side view of a cutter used to produce a pinking cut.

FIG. 6 is a front view of a cutter used to produce a pinking cut andshowing a larger second face.

FIG. 7 is a top view of a cutter used to produce a pinking cut, showingthe perpendicularity of the two faces and showing a larger second face.

FIG. 8 is a top view of a presser foot showing a cutter accommodatingaperture.

FIG. 9 is a side view of a presser foot.

FIG. 10 is an isometric view of a presser foot.

FIG. 11 is a top view of a throat plate showing recesses to permitpassage of a cutter and a perimeter of material retaining means.

FIG. 12 is a perspective view of a cutter producing a straight cut in afragment of work fabric.

FIG. 13 is a perspective view of a cutter producing a pinking cut in afragment of work fabric.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings FIGS.1 illustrates one embodiment of this invention. A conventional sewingmachine 1 comprising a frame 2 and a base 3 contains means (not shown)for imparting reciprocation to a needle bar 4. Fastened to the needlebaris a needle holder 5 and needle holder screw 6.

The sewing machine has a round presser bar 7, positioned adjacent theneedle bar. The presser bar is provided with a flattened machinedportion 8 and threaded fastener 9 which is adapted to accommodate apresser foot 22 as hereinafter more fully described.

Base 3 is provided with an aperture 10 wherein throat plate 28 ismounted.

Inserted into the needle bar is a cutter 11. FIGS. 2, 3 and 4 illustratethe cutter in greater detail. The cutter comprises a shank 12 and ablade 13. The shank consists of upper portion 14 and lower portion 15.The upper portion is provided with a flatened machined surface 16. Whenthe cutter is inserted into needle holder 5 needle holder screw 6 exertsa holding force on surface 16.

Blade 13 consisting of face 17 and 18 is of thickness t. Beveled edges19 and 20 extend in a curving concave are from the shank lower portionterminating at a blade point 21. The inventor has found that thisdesign, a wide upper portion gradually tapering to a point is successfulbecause, the point penetrates the fabric at the start of a needle barreciprocation and the wide upper portion cleanly cuts the fabric at theend of the needle bar reciprocation.

The length 1 of the cutter should be the same as a standard sewingmachine needle. A short cutter would not produce a satisfactory cut anda long cutter would strike the bobbin case at the end of the needle barreciprocation.

FIGS. 8, 9 and 10 illustrate a presser foot 22. The presser foot isformed with a shank 23 and a sole plate 24 extending angularly from theshank bottom. A slot 25 is provided in a U-shaped shank upper portion26. The sole plate is provided with a cutter accommodating aperture 27.

Sole plate width w is equal to the distance w between the outer edges offeed dogs 32 and 34. By providing a presser foot with a wide sole platethe work fabric will be firmly held in place as it is cut. Area a of thecutter accommodating aperture 27 is equal to the throat plate area a,thereby permitting passage of cutter 1 1 as hereinafter more fullydescribed.

The presser foot is attached to the presser bar by passing flattenedmachined portion 8 through the U- shaped shank upper portion 26 andengaging slot 25 on threaded fastener 9.

FIG. 11 illustrates a throat plate 28 another component of the inventorsconversion kit which is adapted for insertion into base aperture 10. Thethroat plate is provided with slots 29, 30 and 31 wherein fabric feeddogs, 32, 33 and 34 respectively are permitted to protrude and engageand advance fabric placed on the sewing machine base. The throat platecontains recesses 35 and 36. Recess 35 is designed to accommodate thepassage of cutter 11. The length and width of this recess beingsufficient to permit passage of cutter 11 therein. Recess 36 concernsanother embodiment of this invention and will be discussed hereinafterwith that embodiment.

Forming a perimeter around the feed dog slots and recesses is retainingmeans 37. The inventor has discovered that when delicate work fabricsuch as voile, shantung or organdy are cut the cutter blade has atendency to draw the fabric down into the recess. By providing aretaining means such as rubber, felt or cork sufficient traction isprovided on the smooth, metallic throat plate thereby preventingmaterial from being drawn into the recess. The retaining material shouldbe nonadhesive so as not to hamper fabric advancing across the throatplate.

FIGS. 5, 6 and 7 illustrate another embodiment of the inventorsconversion kit. These figures illustrate a cutter 41 that can produce apinking cut. The cutter comprises a shank 42 and a blade 43. The shankof this embodiment is similar to the shank 12 of cutter 11 ashereinbefore described. The design of blade 43 distinguishes this cutterover the previously described embodiment.

The blade consists of a first portion 44 and a second portion 45perpendicular to said first portion. Beveled edges 46 and 47 extend in acurving concave are from the shank lower portion terminating at a bladepoint 48.

As can be seen from FIGS. 6 and 7 first portion 44 is larger than secondportion 45. The blade is designed in this manner so as to produce aclean out without any uncut fabric. As the cutter reciprocates in theneedle bar each cut made by second portion 45 is slightly enlarged bythe succeeding cut made by first portion 44. If the two portions weredimensionally equal there would be some uncut fabric and a clean cutcould not be obtained.

Referring to FlG. 11 it can be seen that recess 36 is designed toaccommodate the shape of blade 43. The dimensions of recess slots 49 and50 are calculated to permit passage of first portion 44 and secondportion 45 respectively. The inventor has found that having firstportion 44 and second portion 45 set perpendicular to each otherproduces the most satisfactory cut.

FIG. 12 shows a piece of work fabric 51 being cut with cutter 11 therebyproducing a straight cut 52.

FIG. 13 shows a piece of work fabric 53 being cut with cutter 41 therebyproducing a pinking cut 54.

An ordinary sewing machine is converted into a machine capable ofcutting fabric in the following manner:

An operator inserts a cutter 11 or 41 (depending upon the type of cutdesired by the operator) into a needle holder 5. A presser foot 22 isfastened to a presser bar 7 and a throat plate 28 containing cutterrecesses 35 and 36 is placed into base aperture 10.

The operator then adjusts the sewing machine stitch length and stitchwidth (adjusting means not shown) in order to obtain a satisfactory cutin the work fabric. This adjustment requires a little experimentation onthe part of the operator because the stitch adjusting means variesbetween sewing machine models of different manufacturers.

As the needle bar 4 starts its downward actuation cutter blade 13 firstpenetrates and then cuts work fabric 51 or 53. As the needle bar startsits upward actuation feed dogs 32, 33 and 34 advance uncut fabricbeneath the cutter blade. The blade is actuated once again producinganother cut, slightly overlapping the preceding cut and substantially inline with the preceding cut. This operation is continuted until the workfabric is cut in the desired manner.

It has been shown that throat plate 28 contains a pair of recesses toaccommodate both embodiments. It can be appreciated that a throat platecan be provided wherein one recess is provided without departing fromthe spirit of this invention.

The features of the conversion kit can be modified or altered and suchmodifications or alterations as coming within the scope of the claims ofthis invention are deemed a part thereof.

I claim:

1. A conversion assembly for making a pinking cut adapted for installingas a unit in a sewing machine having a frame, a base with an aperturefor a throat plate, a presser bar for a presser foot, a needle bar,means mounted in the frame for reciprocating the needle bar, meansmounted in the base for feeding fabric, said conversion assemblycomprising:

a. a cutter fixedly inserted into said needle bar, said cuttercomprising i. a shank, and

ii. a blade having a pointed end for penetrating into fabric and a firstcurved concave beveled portion extending from said pointed end to saidshank and a second curved concave beveled portion perpendicular to saidfirst portion and extending from said pointed end to said shank;

b. a presser foot body fastened to said presser bar comprising:

1. a shank, and

ii. a flat sole plate equal to the width of said fabric feeding meansprojecting angularly of said shank and having a cutter accommodatingaperture; and

c. a throat plate placed into said throat plate aperture and containinga recess therein to permit passage of said cutter blade.

2. A conversion assembly adapted for installing as a unit in a sewingmachine having a frame, a base with an aperture for a threat plate, apresser bar for a presser foot, a needle bar, means mounted in the framefor reciprocating the needle bar, means mounted in the base for feedingfabric, for making a pinking cut, said conversion assembly comprising:

a. a cutter fixedly inserted into said needle bar, said cuttercomprising i. a shank, and

ii. a blade having a pointed end for penetrating into fabric and a firstcurved concave beveled portion extending from said pointed end to saidshank and a larger second curved concove beveled portion perpendicularto said first portion and exof said cutter blade.

3. A conversion assembly as recited in claim 2 wherein said throat platerecess further comprises: a first recess and a larger second recessperpendicular to said first recess to permit passage of said cutterblade.

4. A conversion assembly as recited in claim 3 wherein said throat platefurther comprises: a retaining means surrounding said recess to preventmaterial from slipping down into said recess.

5. A conversion assembly as recited in claim 4 wherein said retainingmeans is felt.

1. A conversion assembly for making a pinking cut adapted for installingas a unit in a sewing machine having a frame, a base with an aperturefor a throat pLate, a presser bar for a presser foot, a needle bar,means mounted in the frame for reciprocating the needle bar, meansmounted in the base for feeding fabric, said conversion assemblycomprising: a. a cutter fixedly inserted into said needle bar, saidcutter comprising i. a shank, and ii. a blade having a pointed end forpenetrating into fabric and a first curved concave beveled portionextending from said pointed end to said shank and a second curvedconcave beveled portion perpendicular to said first portion andextending from said pointed end to said shank; b. a presser foot bodyfastened to said presser bar comprising:
 1. a shank, and ii. a flat soleplate equal to the width of said fabric feeding means projectingangularly of said shank and having a cutter accommodating aperture; andc. a throat plate placed into said throat plate aperture and containinga recess therein to permit passage of said cutter blade.
 2. A conversionassembly adapted for installing as a unit in a sewing machine having aframe, a base with an aperture for a throat plate, a presser bar for apresser foot, a needle bar, means mounted in the frame for reciprocatingthe needle bar, means mounted in the base for feeding fabric, for makinga pinking cut, said conversion assembly comprising: a. a cutter fixedlyinserted into said needle bar, said cutter comprising i. a shank, andii. a blade having a pointed end for penetrating into fabric and a firstcurved concave beveled portion extending from said pointed end to saidshank and a larger second curved concove beveled portion perpendicularto said first portion and extending from said pointed end to said shankso that during operation of said sewing machine the cut made by saidfirst portion is enlarged slightly by said second portion therebyproducing a clean cut in said fabric; b. a presser foot body fastened tosaid presser bar comprising: i. a shank, and ii. a flat sole plateprojecting angularly of said shank and having a cutter accommodatingaperture; and c. a throat plate placed into said throat plate apertureand containing a recess therein to permit passage of said cutter blade.3. A conversion assembly as recited in claim 2 wherein said throat platerecess further comprises: a first recess and a larger second recessperpendicular to said first recess to permit passage of said cutterblade.
 4. A conversion assembly as recited in claim 3 wherein saidthroat plate further comprises: a retaining means surrounding saidrecess to prevent material from slipping down into said recess.
 5. Aconversion assembly as recited in claim 4 wherein said retaining meansis felt.